19,240 research outputs found
Projection Operator Formalisms and the Nuclear Shell Model
The shell model solve the nuclear many-body problem in a restricted model
space and takes into account the restricted nature of the space by using
effective interactions and operators. In this paper two different methods for
generating the effective interactions are considered. One is based on a partial
solution of the Schrodinger equation (Bloch-Horowitz or the Feshbach projection
formalism) and other on linear algebra (Lee-Suzuki). The two methods are
derived in a parallel manner so that the difference and similarities become
apparent. The connections with the renormalization group are also pointed out.Comment: 4 pages, no figure
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Self-organizing nonliner output map (SONO): An artificial neural network suitable for cloud-patch based rainfall estimation
Sea breeze: Induced mesoscale systems and severe weather
Sea-breeze-deep convective interactions over the Florida peninsula were investigated using a cloud/mesoscale numerical model. The objective was to gain a better understanding of sea-breeze and deep convective interactions over the Florida peninsula using a high resolution convectively explicit model and to use these results to evaluate convective parameterization schemes. A 3-D numerical investigation of Florida convection was completed. The Kuo and Fritsch-Chappell parameterization schemes are summarized and evaluated
Cosmology and the Hubble Constant: On the Megamaser Cosmology Project (MCP)
The Hubble constant Ho describes not only the expansion of local space at
redshift z ~ 0, but is also a fundamental parameter determining the evolution
of the universe. Recent measurements of Ho anchored on Cepheid observations
have reached a precision of several percent. However, this problem is so
important that confirmation from several methods is needed to better constrain
Ho and, with it, dark energy and the curvature of space. A particularly direct
method involves the determination of distances to local galaxies far enough to
be part of the Hubble flow through water vapor (H2O) masers orbiting nuclear
supermassive black holes. The goal of this article is to describe the relevance
of Ho with respect to fundamental cosmological questions and to summarize
recent progress of the the `Megamaser Cosmology Project' (MCP) related to the
Hubble constant.Comment: 10 pages, 7 postscript figures (8 ps files), IAU Symposium 287, uses
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Electric foot-shock stress drives TNF-alpha production in the liver of IL-6-deficient mice
Objectives: Accumulating evidence has shown that interleukin-6 (IL-6) has pleiotropic effects on a variety of biological functions, including its antiapoptotic potential during liver injury. Our previous work demonstrated that restraint stress-induced elevation of plasma IL-6 negatively regulates plasma tumor necrosis factor-alpha (TNF-alpha). Herein, we further clarified the mechanism underlying the above finding and investigated the effect of IL-6 on liver apoptosis triggered by stress. Methods: Male C57BL/6J and IL-6-deficient C57BL/SV129 mice were exposed to 1 h of electric foot-shock stress. Thereafter, the serum, liver and spleen TNF-alpha levels were measured at several time points. Serum alanine aminotransferase (ALT), liver caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling ( TUNEL) activities were analyzed to evaluate the severity of liver injury and apoptosis. Results: The liver, but not the spleen, of the IL-6-deficient mice exhibited a significant increase in TNF-alpha level after stress in parallel with serum TNF-alpha elevation, whereas no such TNF-alpha responses were found in the wild animals. No significant differences in stress-induced elevation of serum ALT levels, liver caspase-3 activities and the number of TUNEL-positive hepatocytes were found between the wild and IL-6-deficient mice. Conclusions: Taken together, these results indicate that IL-6 may play a critical role in suppressing TNF-alpha production in the liver, thereby decreasing the blood TNF-alpha level. In contrast, IL-6 secretion was shown to have no protective effect on stress-triggered liver injury. Copyright (C) 2004 S. Karger AG, Basel
Absolutely free extrinsic evolution of passive low-pass filter
Evolutionary electronics is a brunch of evolvable hardware, where the evolutionary algorithm is applied towards electronic circuits. The success of evolutionary search most of all depends on variable length representation methodology. The low-pass filter is a standard task in evolutionary electronics to start with. The results of evolution enable one to qualify whether the methodology is good for further experiments. In this paper the maximum freedom for evolutionary search has been proclaimed as a main target during development of new VLR methodology. The introduction of R-support elements enables to perform an unconstrained evolution of analogue circuits for the first time. The proposed algorithm has been tested on the example of analogue low-pass filter. The experimental results demonstrate that the evolved filter is comparable with filters evolved previously using genetic programming and genetic algorithms techniques. The obtained results are compared in details with low-pass filters previously designed
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